Numerical study of efficiencies for box type solar cooker with internal reflectors

En este trabajo se muestran los resultados del estudio de las eficiencias termodinámicas de 1.a y 2.a ley aplicadas a 4 arreglos diferentes de estufas solares de tipo caja con reflectores internos. La estufa solar tiene 2 vidrios en su cubierta para disminuir la pérdida de calor por radiación y convección, y crear así el efecto invernadero. El interior de la estufa tiene espejos colocados a diferentes ángulos para dirigir la radiación solar hacia un recipiente con agua que se encuentra también dentro de la estufa. Los resultados obtenidos están basados en las temperaturas de calentamiento del agua, las cuales fueron obtenidas por medio de una simulación numérica que permite comparar los 4 arreglos de estufas solares bajo condiciones idénticas. El tratamiento de los resultados revela que la cantidad de energía que impacta en las estufas solares no es aprovechada de manera adecuada para los fines de calentamiento de agua. La mayor parte de la energía aprovechable se almacena en los vidrios de la tapa, lo que evidencia la necesidad de trabajar en el desarrollo de mejores materiales para mejorar tal situación.In this work, results of efficiencies for first and second law of thermodynamics applied to four box-type solar cookers with internal reflectors are shown. The solar cooker has two glasses on its cover to diminish the losses of heat for radiation and convection, besides creating the effect hothouse inside the cooker. The interior of the cooker has flat mirrors placed at different angles to reflect the solar radiation toward a recipient with water inside the cooker. The obtained results are based on heating water temperatures which were obtained by means of numeric simulation, allowing comparison under identical conditions of four solar cookers. The treatment of the results revealed that the quantity of energy that impacts on the solar cookers is not used in right way for the heating water ends. Most of the profitable energy is stored in the glasses of the cover, what evidences the necessity to work in the development of better materials to diminish such situation.Peer Reviewe

Experimental determination of convection heat transfer coefficient for eggplant, zucchini and potato using a solar cooker box-type

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.In this work, experimental results to determine the convection heat transfer coefficient in the cooking process of eggplant, zucchini and potato using a solar cooker box-type are presented. Experimental data of temperatures for the fluid (water), surface and central point of the vegetables were used. To determine the convection coefficient, the vegetables were modeled as cylinders and a sphere according to their forms. The temperatures evolution was defined using thermocouples located at water, surface and central point in the vegetables. In the experimental process a NI Compact Field Point was used as acquisition data system which allows measure temperatures in simultaneous form. Also, a solar simulator as source of energy for the solar cooker function was used. Using heat transfer convection equations in transitory state and the temperatures measured, the Biot number and the convection coefficient were determined. To define how the cooking process occurs, diffusivity, density and heat specific were considered. Agree to results, the highest values to convection coefficient are obtained for eggplant while the minor values correspond to potato. The experimental tests for the cooking process were done in similar conditions which allow comparing results and generating a discussion for the same ones.dc201

HEATING OF BEE HONEY, OLIVE OIL, MILK AND WATER IN A SOLAR COOKER BOX TYPE WITH INTERNAL REFLECTORS

ABSTRACT Numerical simulation results are shown to determine the heating in liquids when a solar cooker box type with internal reflector is used to this end. The data evaluated correspond to temperature values from bee honey, olive oil, milk and water when they are heated in the solar cooker. The maximum simulation temperatures reached are 91.8, 91.6, 86.2 and 85.3 ºC that correspond to bee honey, olive oil, milk and water respectively. A comparative between simulation and experimental results also are shown. The values presented evidence the influence of the specific heat in each fluid considered. In the numerical simulation were used solar radiation and environment temperature values for February 26, 2006 in Mexico City. The experimental data were acquired using an Eppley piranometer and a Field Point device and were used as initial numerical conditions in the simulation. The processing information acquired was made using the LabView 7.0 software

Análisis numérico de la convección natural en recintos cerrados con distinto factor de forma

pEn este trabajo se utilizó el análisis numérico, aplicando el programa de simulación para ingeniería ANSYS, para establecer la distribución de temperaturas, densidad y velocidades vertical y horizontal en una cavidad cerrada con relación geométrica alto/ancho (emH/E/em) del sistema de 0.5, 1 y 2, temperatura constante en la pared vertical izquierda y derecha de 50 y 20 °C, respectivamente, y condición de frontera adiabática en las paredes horizontales. Lo anterior para un número de Prandtl de 4.83 y Rayleigh de 5.84x10sup7/sup. Al comparar los resultados entre el sistema con emH/E /em= 2 y emH/E /em= 1, se encontró que el valor máximo positivo de la velocidad vertical se incrementó un 26.29 %, el de la velocidad horizontal disminuyó 72.75 % y la temperatura en la zona central de la cavidad disminuyó un 2.46 %. Por otro lado, al comparar los resultados del sistema emH/E /em= 0.5 y emH/E /em= 1, se encontró que el valor máximo positivo de la velocidad vertical aumentó un 7.24 %, el de la velocidad horizontal se incrementó 34.08 % y la temperatura de la zona central del sistema disminuyó un 3.70 %./pp /pp /ppstrongPalabras claves:/strong Convección natural; Cavidad cerrada; ANSYS/p pDOI: a href="http://dx.doi.org/10.5377/nexo.v24i1.589"http://dx.doi.org/10.5377/nexo.v24i1.589/a/p pNexo, Vol. 24, No. 1, pp. 3-10, 2011/pp /

Numerical analysis of stream function, vorticity and circulation for a rotating flow with rigid boundary

En este trabajo se obtienen y analizan los campos de las funciones vorticidad tangencial, circulación y corriente meridional, que se generan en el interior de un cilindro cerrado que tiene el fondo giratorio y la tapa superior y envolvente sin movimiento. Los resultados se presentan mediante gráficas en las que se comparan dichas funciones, para un número de Reynolds de 3x10 4 y para un factor de forma (alto/radio) del recipiente de 0.5, 1.0 y 2.0. Se encontró al comparar el sistema con relación geométrica 2 respecto al 1, que la función corriente disminuye 29.63%; que la circulación permanece constante y que la vorticidad se reduce un 65.91%. Por otro lado, al comparar el sistema con relación geométrica 0.5 respecto al de 1, se encontró que la función corriente aumenta 1.4 veces, que la circulación se incrementó 3.45 veces y que la vorticidad aumentó 0.7 veces. Los resultados anteriores dan una idea del comportamiento de las funciones corriente, circulación y vorticidad tangencial para las relaciones geométricas antes mencionadas, pero se requiere de un mayor análisis para poder utilizar estos resultados al caso particular de mezclado o de alguna otra aplicación práctica de ingeniería.The tangential vorticity function, circulation and meridian stream that form in a closed rotating cylinder are analyzed. The cylinder has a rotating bottom whereas the lateral surface and the top are fixed. The results are presented as graphs that compare the mentioned functions for different aspect ratios. The comparing aspect ratios: 0.5, 1.0 and 2.0. In comparing the 2.0 aspect ratio versus the 1.0 aspect ratio; it is found that the stream function diminished a 29.63%, whereas the circulation does not change and the vorticity decreases 65.91%. On the other hand comparison of the cylinder with aspect ratio 0.5 against the one with aspect ratio 1; gives that the stream function increases 1.4 times; that the circulation increases 3.45 times and the vorticirty increases 0.7 times. The analysis was made for a 3 x 104 Reynolds number. The mentioned results give an indication of the influence of the aspect ratio as to the motion inside the cylinder. Further investigation is required in order to apply the results to particular conditions of mixing or another practical application.Peer Reviewe

High-throughput genotyping of single nucleotide polymorphisms with rolling circle amplification

BACKGROUND: Single nucleotide polymorphisms (SNPs) are the foundation of powerful complex trait and pharmacogenomic analyses. The availability of large SNP databases, however, has emphasized a need for inexpensive SNP genotyping methods of commensurate simplicity, robustness, and scalability. We describe a solution-based, microtiter plate method for SNP genotyping of human genomic DNA. The method is based upon allele discrimination by ligation of open circle probes followed by rolling circle amplification of the signal using fluorescent primers. Only the probe with a 3' base complementary to the SNP is circularized by ligation. RESULTS: SNP scoring by ligation was optimized to a 100,000 fold discrimination against probe mismatched to the SNP. The assay was used to genotype 10 SNPs from a set of 192 genomic DNA samples in a high-throughput format. Assay directly from genomic DNA eliminates the need to preamplify the target as done for many other genotyping methods. The sensitivity of the assay was demonstrated by genotyping from 1 ng of genomic DNA. We demonstrate that the assay can detect a single molecule of the circularized probe. CONCLUSIONS: Compatibility with homogeneous formats and the ability to assay small amounts of genomic DNA meets the exacting requirements of automated, high-throughput SNP scoring

Chronic depression: development and evaluation of the luebeck questionnaire for recording preoperational thinking (LQPT)

<p>Abstract</p> <p>Background</p> <p>A standardized instrument for recording the specific cognitive psychopathology of chronically depressed patients has not yet been developed. Up until now, preoperational thinking of chronically depressed patients has only been described in case studies, or through the external observations of therapists. The aim of this study was to develop and evaluate a standardized self-assessment instrument for measuring preoperational thinking that sufficiently conforms to the quality criteria for test theory.</p> <p>Methods</p> <p>The "Luebeck Questionnaire for Recording Preoperational Thinking (LQPT)" was developed and evaluated using a german sample consisting of 30 episodically depressed, 30 chronically depressed and 30 healthy volunteers. As an initial step the questionnaire was subjected to an item analysis and a final test form was compiled. In a second step, reliability and validity tests were performed.</p> <p>Results</p> <p>Overall, the results of this study showed that the LQPT is a useful, reliable and valid instrument. The reliability (split-half reliability 0.885; internal consistency 0.901) and the correlations with other instruments for measuring related constructs (control beliefs, interpersonal problems, stress management) proved to be satisfactory. Chronically depressed patients, episodically depressed patients and healthy volunteers could be distinguished from one another in a statistically significant manner (p < 0.001).</p> <p>Conclusion</p> <p>The questionnaire fulfilled the classical test quality criteria. With the LQPT there is an opportunity to test the theory underlying the CBASP model.</p

Connector Inversion Probe Technology: A Powerful One-Primer Multiplex DNA Amplification System for Numerous Scientific Applications

We combined components of a previous assay referred to as Molecular Inversion Probe (MIP) with a complete gap filling strategy, creating a versatile powerful one-primer multiplex amplification system. As a proof-of-concept, this novel method, which employs a Connector Inversion Probe (CIPer), was tested as a genetic tool for pathogen diagnosis, typing, and antibiotic resistance screening with two distinct systems: i) a conserved sequence primer system for genotyping Human Papillomavirus (HPV), a cancer-associated viral agent and ii) screening for antibiotic resistance mutations in the bacterial pathogen Neisseria gonorrhoeae. We also discuss future applications and advances of the CIPer technology such as integration with digital amplification and next-generation sequencing methods. Furthermore, we introduce the concept of two-dimension informational barcodes, i.e. “multiplex multiplexing padlocks” (MMPs). For the readers' convenience, we also provide an on-line tutorial with user-interface software application CIP creator 1.0.1, for custom probe generation from virtually any new or established primer-pairs

Molecular techniques for pathogen identification and fungus detection in the environment

Many species of fungi can cause disease in plants, animals and humans. Accurate and robust detection and quantification of fungi is essential for diagnosis, modeling and surveillance. Also direct detection of fungi enables a deeper understanding of natural microbial communities, particularly as a great many fungi are difficult or impossible to cultivate. In the last decade, effective amplification platforms, probe development and various quantitative PCR technologies have revolutionized research on fungal detection and identification. Examples of the latest technology in fungal detection and differentiation are discussed here

Choice of the initial antiretroviral treatment for HIV-positive individuals in the era of integrase inhibitors

BACKGROUND: We aimed to describe the most frequently prescribed initial antiretroviral therapy (ART) regimens in recent years in HIV-positive persons in the Cohort of the Spanish HIV/AIDS Research Network (CoRIS) and to investigate factors associated with the choice of each regimen. METHODS: We analyzed initial ART regimens prescribed in adults participating in CoRIS from 2014 to 2017. Only regimens prescribed in >5% of patients were considered. We used multivariable multinomial regression to estimate Relative Risk Ratios (RRRs) for the association between sociodemographic and clinical characteristics and the choice of the initial regimen. RESULTS: Among 2874 participants, abacavir(ABC)/lamivudine(3TC)/dolutegavir(DTG) was the most frequently prescribed regimen (32.1%), followed by tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC)/elvitegravir(EVG)/cobicistat(COBI) (14.9%), TDF/FTC/rilpivirine (RPV) (14.0%), tenofovir alafenamide (TAF)/FTC/EVG/COBI (13.7%), TDF/FTC+DTG (10.0%), TDF/FTC+darunavir/ritonavir or darunavir/cobicistat (bDRV) (9.8%) and TDF/FTC+raltegravir (RAL) (5.6%). Compared with ABC/3TC/DTG, starting TDF/FTC/RPV was less likely in patients with CD4100.000 copies/mL. TDF/FTC+DTG was more frequent in those with CD4100.000 copies/mL. TDF/FTC+RAL and TDF/FTC+bDRV were also more frequent among patients with CD4<200 cells//muL and with transmission categories other than men who have sex with men. Compared with ABC/3TC/DTG, the prescription of other initial ART regimens decreased from 2014-2015 to 2016-2017 with the exception of TDF/FTC+DTG. Differences in the choice of the initial ART regimen were observed by hospitals' location. CONCLUSIONS: The choice of initial ART regimens is consistent with Spanish guidelines' recommendations, but is also clearly influenced by physician's perception based on patient's clinical and sociodemographic variables and by the prescribing hospital location